Conventionally, lenticular lens systems have been known as image display techniques for presenting an observer with a 3D (three-dimensional) image by separating a region in which images displayed by image display means are observed (e.g. Patent Document 1).
An image obtained by combining images of an object captured from a few directions is displayed on a liquid crystal panel as the image display means. Lenticular lenses as image separation means are situated in front of the liquid crystal panel. The lenticular lenses are inclined at a predetermined angle to a vertical axis of the image display panel. An observer observes the liquid crystal panel through the lenticular lenses. Observed portions of the liquid crystal panel are changed by positions of eyes due to effects of the lenses. Consequently, a region in which each viewpoint image is visible is separated, so that the left and right eyes of the observer observe the image from different viewpoints. The brain of the observer recognizes the image as a 3D image due to parallax of both eyes as a difference between the different viewpoint images.
A positional relationship among the liquid crystal panel, the lenticular lenses and a viewpoint of the observer causes a change in observation region on the liquid crystal panel observed from a viewpoint through the lenticular lenses. There are a region of pixels and a region of a black matrix formed by electrodes and alike on the liquid crystal panel.
FIG. 15 is a schematic view of a part of pixels of a liquid crystal panel as image display means according to conventional arts. In FIG. 15, many pixels 11 are arranged in the horizontal direction and the vertical direction on the liquid crystal panel. A region other than the pixels 11 is a black matrix 12 in which black pigments are coated after formation of electrodes and alike not to display images. Lenticular lenses (not shown) are inclined at a predetermined angle to the vertical direction of the liquid crystal panel.
An observer observes a linear observation region 21, which is indicated by the dotted line, from a viewpoint through the lenticular lenses. FIG. 15 shows a state that the observation region 21 passes through a middle of the pixels 11 of the liquid crystal panel. In FIG. 15, the observation region 21 bridging between adjacent pixels in the horizontal direction is superposed with the black matrix 12. This region is indicated by the thick lines. The observation region 21 bridging between adjacent pixels in the vertical direction is also superposed with the black matrix 12. This region is indicated by the bold lines. Because the black matrix 12 is a region without image light emission, the region superposed with the observation region 21 is a non-luminous region.
FIG. 16 shows a state that a position of the observation region 21 on the liquid crystal panel moves so that the observation region 21 passes through a center (the black dot) of a pixel 11 of the liquid crystal panel. The observation region 21 bridging between the pixels 11 is superposed with the black matrix 12. This region is indicated by the thick lines. The superposed region is also a non-luminous region.
A total length of the non-luminous regions in FIG. 15 is longer than a total length of the non-luminous regions in FIG. 16. Specifically, a total length of the thick lines in FIG. 15 is as long as a total length of the thick lines in FIG. 16. The total length of the non-luminous regions in FIG. 15 is longer than the total length of the non-luminous regions in FIG. 16 by a total length of the bold lines 13. Therefore, a screen in FIG. 15 is darker than a screen in FIG. 16. This means that brightness of an observed screen is changed by a position of the observer to cause moire, which results in degraded quality of 3D images.
Patent Document 1: JP H09-236777 A